Chemical bomb



April 10, 1956 H A RlCARDs, JR" ETAL 2,741,177

CHEMICAL BOMB 2 Sheets-Sheet l Filed Nov. '7, 1944 ma. Tm AN M K LT@ EMGm RLS mmm GW R m m A R RRF AE m@ R .0 AC D mw M m Hw April 10, 1956 H.A. RICARDS, JR., EIAL 2,74%177 CHEMICAL BOMB 2 Sheets-Shen 2 Filed Nov.'7, 1944 MLU? Patented Apr. 10, 1956 criar/ucar. norm Harold A. Ricards,fr., Cranford, George L. Matheson, Union, Lyle M. Cooper, Railway,William T. Knox, Jr., Roselle, and Francis R. Russell, Scotch Plains,hl. assignors to the United States of America as represented by theSecretary of War Application November 7, 1944, Serial No. 562,368

1 Claim. (Cl. 162--6) The invention described herein may be manufacturedand used by or for the Government, for governmental purposes, withoutthe payment to us of any royalty thereon.

'i'his invention relates to a type of aerial drop bomb designed to ejectfrom its tail a chemical agent, such as incendiary material, and throwsuch materials against surrounding objects after impact. Y

Prior to the present invention it was well recognized that disseminationof chemical agents from aircraft could constitute a serious threat inwarfare, but the tactical ernployment of chemical bombs was largelyhandicapped by lack of a suitably designed bomb. In general there weretwo types of bombs, the intensive'and scatter types. The intensive typewas designed to penetrate a building by a direct hit and remain as aunit while functioning in a very restricted area if the bomby lands oncombustible material. This type is represented by the thermit-lledincendiary bomb. The scatter type requires the use of a high explosiveburster suiciently powerful to rupture the entire bomb body on impactand diffuses or scatters very small particles of the chemical charge inall directions over an area surrounding the ruptured bomb body. Both ofthese types have a number of limitations. The intensive typenecessitates a thick body wall and is not effective unless it landsexactly on a spot where the incendiary action can be started. It isknown that only a small percentage of intensive type incendiary bombsland where they can initiate destructive action. The scatter 'type bombfails to function effectively in that the charge becomes too widelyspread out in small particles. A large proportion of small scatteredparticles from a scatter type incendiary bomb fail to ignite, and thosethat are ignited have too little heat and flame action to initiateburning of a structure they Contact except in a few favorablecircumstances. A large part of the diffused charge from the scatter typebomb is uselessly directed upwardly and downwardly.

An object of the present invention is to provide a type of bomb whichhas an advantageous loading eiciency by virtue of its high active agentcapacity relative to the weight of the bomb, good security qualities forhandling, clustering adaptability for area pattern bombing, anddesirable distribution characteristics.

Another object is to provide a type of bomb simple and economical formanufacture, assembly, and use. Further objects and advantages willbecome apparent from the following description.

Broadly, for accomplishing the objects of the present invention, a bombhas been designed to eject forcefully from the tail end of the bomb bodya chemical charge to be distributed. More particularly, the bomb usedfor incendiary action is provided with a combination percussion and timefuze which permits the bomb to fall to rest on its side afterpenetration into a target so that a mass of viscid incendiary materialcan be thrown out horizontally like a single projectile from a mortar tostrike an object where a concentrated incendiary action can be startedin the path of its trajectory. While ejection of the charge as a singleprojectile is desirable when the bomb is used with an incendiary agent,the bomb is adapted also for discharging other types of agents, such asa vesicant liquid in a thick spray, powdered material in a dense cloud,or the like, when spreading of such agents over an area is desired inthe form of a concentrated mass travelling rapidly over the ground.

Various features of the bomb will be described in further detail withreference to illustrations of embodiments in the accompanying drawingswhich form part of this specification.

in the drawings:

Figure l shows a vertical sectional view of a standardized tail ejectionincendiary bomb;

Figure 2 shows an elevational View 0f the tail end of the bomb;

Figure 3 shows a nose end view of the bomb in elevational view andpartly in section;

Figure 4 shows an elevational full view of the bomb assembled and withnose end at bottom;

`Figure 5 shows an enlarged longitudinal cross-section of a safetyplunger assembly used in the type of fuze shown in Figs. l and 6;

Figure 6 shows a cut away view in a fragmentary section of the nose endof the bomb modified to contain an anti-personnel fragmentation unit;

In the drawings, similar parts are given the same reference characters.

Referring to the drawings, and particularly to Figs. l to 5, casing l,made conveniently of about 18 to 20 gage pressed sheet steel, extendssubstantially the entire length of the bomb and forms a leakproofcontainer for the assembly described hereinafter. A nose cup 2 made ofsheet steel, preferably thicker than casing l, is fixed into the nose(bottom) end of casing l, forming a blunt nose and housing a suitablecombination percussion and time fuze assembly 3 together with a chargeof ignitingpropellant powder 4l. The powder 4 may be inclosed in thinwalled cellulose nitrate plastic containers, which fit into the nose cupadjacent fuze assembly 3.

The fuze assembly 3 is screwed at its threaded head end into a threadedhole 5 in the casing ll and nose cup 2. rThe fuze shown comprises afiring mechanism assembly c-f a die cast aluminum base alloy 6 having awell for holding a primer cap '7 and supporting a hinged striker 8 ofdie cast aluminum or steel with a torsion spring 9 for restrainingmovement of the striker 8 until the movement is caused by sufficientimpact force on the bomb. A safety plunger assembly iti is centrallyrecessed in the head end of the fuze base 6, where, in unarmed position,a spring held plunger is pressed inwardly under the striker to preventmovement thereof. A lead spitter fuse ll leads in a groove through thebase 6 from the primer cap well under primer cap 7 to a booster chargel2 contained in a cellulose nitrate plastic cup i3. The tiring mechanismassembly is protectively encased in a steel cylinder i4.

A disc shaped steel impact diaphragm plug 15 is mounted in and above ahole in the impact diaphragm l5, which is securely brazed to the upperedge ofV nose cup 2. Diaphragm 1o and plug' 15 serve as reinforcementfor a thin sheet steel diaphragm l? brazed to the casing l to act as aleakproof seal between the explosion chamber in nose cup 2 and the llingi8. v

Gelled or viscid fuel charge 18,' occupying the major part of the bomb,is preferably enclosed in a cheesecloth sock i9, the upper end 20 ofwhich is tied securely by a piece of string 21.

in a standardized 6-lb. incendiary oil bomb of the type shown in Fig. lthe casing is about 191/2 inches long, hexagonal in shape, 27/s incheswide across the ats,

.nd weighs complete, filled and fuzed, about 6 lbs. Nearly .1/2 lbs. ofthis weight is a gelled gasoline charge. A ail cup 22, made of sheetsteel, is mounted in the tail upper)V end of the casing 1 andV iscrimped thereto to erm a leakproof seal but is releasable when subjectedto predetermined pressure from within the casing. v As a simplifiedstabilizing means, tail streamers 23, vhich are lengths of mildew-proofcloth, are attached it one end to a retainer cup 24 spot-welded at thebottom o the tail cup proper 22. A retainer ring 25 ts over he retainercup 24 to securely hold the ends of treamers 23. When the bomb falls,the free ends of the :trearners 23 ily out, retarding and stabilizingdescent of he bomb, so that the bomb falls in approximately a /erticalposition at a regulated terminal velocity, e. g., if about 250 ft. persecond.

in operation, when the bomb is separated from a cluster lropped byaircraft, the plunger in the safety plunger' assembly 1@ is retracted bya coiled spring away frorrr mder the striker to arm the fuze, theplunger being no Longer pressed inwardly by an adjacent bomb in the:luster: Upon impact of the bomb at its nose end on a target surface,inertia of the weighted portion at the swinging end of the striker 3pivotally mounted on the base 6 forces the striker 8 to overcome therestraint of the torsion spring 9 and to swing on hinge pin pivot 9awith its ring pin directed toward the primer material in primer cap 7.The firing pin of striker upon being driven into the primer chargedashes the primer, which in turn ignites an underlying end of the leadspitter fuse 11. The lead spitter fuse 11 formed of black powder andcollodion compressed in a lead tube burns to its opposite end in aperiod of about l to 5 seconds, giving a desired delay action, whichpermits the bomb to penetrate the target surface fairly heavy roofconstructions, including common sheet metal and tile roofs, and ifdesired, also to penetrate one or more iloorings in a building duringthe delay in the lead spitter fuse, which permits the bomb to penetratesuch structures and fall to rest on its side before functioning.

Referring to Fig. 5, the safety plunger assembly lil is of a type whichhas been manufactured for use in standardized thermit incendiary bombs,but an easily made modification is desirable on account of therelatively small distance of travel of the hinged striker in the fuzeillustrated in Figs. 1 and 5. Safety plunger assembly 1t) comprises athin-walled sleeve 27 formed of brass, guild-V ing metal, or the like,for housing a coil spring 2S under compression and the stem 29 of aplunger pin. The plunger pin has a flange 36 which bears against one endof the coil spring 2S and prevents the plunger pin from being entirelyejected from the sleeve 27. In the unarmed position, the plunger pin hasa button end 33t projecting outside the sleeve 27, and in an armedposition, the plunger pin is pressed inwardly against the coil spring 28so that the narrow end of the stern 29 of the plunger pin opposite thebutton end 31 projects into the fuze underneath the striker 8 to preventmovement thereof. A thin washer 32, itted closely around the plunger pinstern 29 between the spring 28 and the inner end of the sleeve 27reduces the hole diameter at this end of the sleeve and thereby givesbetter control of the plunger movement. The fuze is maintained unarmedby pressure of an adjacent bomb in a cluster against the button 31 ofthe plunger pin.

The ignited first ire charge 12 ignites the ignitingpropellant charge 4adjacent the fuze unit 3, and explosion of the propellant powder causesan immediateincrease in pressure which lifts the impact diaphragm plug15, ruptures the sealing diaphragm 17 forces out of the tail cup 22, andviolently ejects the mass of thickened fuel charge enclosed in the sockas a single flaming projectile with suicient force to Ysend it 25 to 200feet or farther, or to where it is generally intercepted by an uprightlstructure such as the wallor eaves of a building.

4of the propellant charge.

The ejection mechanism depends on Vthe ability of burning propellantpowder in the charge i to create suicient pressure in the explosionchamber confined within the nose cup 2 to shear the sealing diaphragm17, and shoot out the fuel charge from-the tail end of the bomb so thatthe bomb acts like a mortar, with the fuel charge being ejected by itsown piston action. lt has been found that if the impact diaphragm plug15 is made wide,

enough to fit so that its periphery is close to the inner wall of casingl to have a piston action, that the plug tends to disrupt the casingwhen it is lifted by the propellant charge explosion; also, such aclosely tted diaphragm would be prevented from moving by smalldeformations in the casing 1, such as may result from slight bucklingupon impact. Accordingly, a substantial clearance is provided betweenthe diaphragm plug 15 and the inner wall ofthe casing 1. Satisfactoryperformance is obtained by having the impact diaphragm plug 15 in theform of a dished plate about 0.2 inch thick resting Von diaphragm disc16 over the central hole `about 1.5 inches in diameter in this disc andarched toward the tail. The thin sealing diaphragm 17 Vfits snugly overthe impact diaphragm plug 15, the impact diaphragm, and nose cup 2. Thesealing diaphragm 17 may not have suicient Y by diaphragm plug 15 anddiaphragm 16. The impact diaphragm plug 15 acts somewhat in the fashionof a check valve which is opened by the explosive pressure An asbestosgasket 26 may be placed under the diaphragm plug 15 to keep it frombeing fused to itsY seat on diaphragm le, and the arrange- Y ment issuch thatv the-impact diaphragm plug 1S is held in its proper position.f

f The cloth sock 19 made'of cheesecloth has adequate mechanical strengthto remain as an intact enclosure of the entire fuel charge duringejection; moreover, the sock improves ignition and helps to give thedesired distribution, since it holds the Vfuel together to startignition of the entire mass and allows the burning fuel'to spread out asa large gob over. the surface of a structure hit by the sock enclosedcharge where the sock is finally broken. j i

From a largenumber of tests it was found that the use of a cloth sockfor enclosing a viscid oil incendiary charge in the tail ejection typebomb of the present invention is highly advantageous for obtainingcomplete ejection, positive ignition, and good distribution of theejected fuel charge. Although the cloth sock may be made from variousfabrics, it is preferably made from a loosely woven material, such as, anetting, gauze,'or cheesecloth. A suitable cheesecloth is covered inFederal Specication CCC-C-271; Type 1 (unbleached) with a warp threadcount 36, Vfilling thread count 23; approximate weight of 14 lbs. peryard; width of 36V inches; and known commercially as Grade 50cheesecloth. The size of the sock depends upon the measurements of thebomb.

The sock is made with simplicity and is preferably oversize relative tothe volume of the filling. Preferably the sock should be of such lengthso that its top can be folded over the top of the bomb casing 1 with thetail cup 22 removed during the lling operation.

For a 5-1b. bomb, 14%/2 inches long and 3 inches in diameter, thecheesecloth is cut into swatches of 18 inches by 121/2 inches. The clothis folded once lengthwise and machine stitched along the bottom andalong one side j to form a long bag having a distance of about 5% inchesfrom fold to seam. The sock need not be turned inside out. After illingwithrfuel in the bomb, leaving an out- 'age space of about 5% to 8%, thetop of the bag is tied closed by ystring 21.

lMany types of thickened and gelled fuels may be used with the sockenclosure in tail ejection bombs. The fuel should have a 'consistencywhich is not too thin with a ltendency 'to "excessive flash burning nortoo hard with a and type of propellant powder.

tendency to rebound upon striking a hard surface. Brieiiy, among typesof viscid fuels which may be used are:

Fuels gelled by soaps;

Fuels gelled or thickened by resins, e. g., rubber, polybutenes,isobutyl methacrylate, etc.;

Fuels thickened by gums or other resnous materials, e. g.,

rosin, asphalt, and the like; and

Fuels thickened by mixtures of soaps and resin.

A preferred type of gelled fuel may be made by admixing with naphthahydrocarbons about 7 to 14% by weight of coprecipitated aluminum soapsof stearic acid and oleic acid, or mixtures of such soaps with soaps ofother acids, such as, cocoanut oil fatty acids, and naphthenic acids.The gelled or thickened fuels may include fuel oils less volatile thangasoline, such as, kerosene and even viscous residual oils. They maycontain in suspensionnely divided pyrophoric metals, such as powderedmagnesium, oxidizing agents, wood meal, carbon, sodium, or othercombustion promoting substances. Such incendiary oils on combustion candevelop much more heat than burning thermit mixtures compared on thesame weight basis.

Fibrous materials, such as, cotton waste, sisal, excelsior, and thelike, to some extent act as binders when added to an incendiary oilfuel, but the use of these binders is not necessary when the fuel isenclosed in a cloth sock and particularly when the fuel is heaved from atail ejection bomb horizontally.

in demonstration tests and in practical bombs, a number 4 primer cap wasused in the fuse 3 with a l to 5 second delay lead spitter fuse. Thefirst fire charge 12 was about l gram of Army Grade A No. 4 glazed blackpowder. The ignition-ejection charge placed in each bomb was about 4 to7 e. g. of powdered magnesium coated with about 3% boiled linseed oiland about 4 to 7 g. of Grade A No. 4 Army glazed black powder. Theprimer cap is covered in U. S. Army Specification (Primer New No. 4), atype of primer commercially manufactured for smokeless powder shotshells. The lead spitter fuse is a commercial type of fuse cut intoabout 'Ma inch lengths.

From studies of many tests it was found that between about 2 and 21/2lbs. of incendiary oil charge is an optimum quantity in each bomb forstarting fires in typical structures. The incident of effective lirestarting decreased rapidly in reducing the quantity of charge below thisrange, whereas the use of larger quantities was found unnecessary. Thecasing and the firing mechanism in the bomb can be appropriatelydesigned for efficient clustering, suitable ballistics, and targetpenetration with an optimum quantity of the fuel charge in the bomb.

Efficient ejection is obtained generally with the following relationshipof diaphragm strength, tail cup release pressure, powder charge and fuelviscosity:

Diaphragm (sealing) thickness, about 0.008 inch (about 400 to 500 lb./sq. in. rupture pressure resistance).

Tail cup release pressure, about 100 to 150 lb./sq. in.

maximum.

Black powder charge, about 4 to 14 g.

Magnesium powder charge, about 4 to 7 g.

Fuel viscosity for sock inclosed charge, about 300 to 2000 g. Gardner.

Volume ratio of powder chamber to propellant powder charge, less than:1.

The kind of ejection may be varied with the amount A typical compositionof black powder is about 75 weight percent potassium nitrate, 15%charcoal, and about 10% sulfur. Differences in granulation and surfacecharacteristics of the powder affect changes in the speed of burning andrate of pressure development.

in practical tail ejection bombs designed to hold optimum quantities ofan incendiary oil charge, too low an amount of propellant powder, lessthan about 4 g.,

develops insufficient pressure to properly eject the incendiary charge;whereas amounts of propellant powder larger than about 14 g. tend todevelop excessive pressures. Various igniting materials may be added tothe propellant powder charge to act as a source of hot particles forignitng the incendiary oil charge as it is being ejected. Powderedmagnesium was found to be a very satisfactory igniting material,particularly when coated with boiled linseed oil and to give close toignition over a complete temperature range from minus 40 F. to about 150F. Other igniting materials may be used such as powdered aluminum withan admixture of oxidizing and promoting substances, such as bariumnitrate and sulfur.

With the thin-walled casing having a substantially uniform polygonal,preferably hexagonal, cross-section from its nose to its tail, exceptfor a slight crimping with a single seam at the tail end, the bomb has ahigh loading and ejection ehciency. With this shape, an extensibleflight stabilizer, and suitably disposed fuse having a safety plunger,the' bomb is adapted for efficient clustering with standardized aimableclustering means.

The tail ejection bomb may be provided with a delayed actionanti-personnel element or burster to discourage approach by firefightersand increase damage in the vicinity of the bomb. A suitable burster orfragmentation unit is illustrated in Fig. 6.

Referring to Fig. 6, fixed into the casing 1 under the nose cup 2, whichholds the fuse and powder charge, is a delay fuse cup 32 for holding. ahelically wound delay fuse 33 in varying lengths. The delay fuse 33 maybe of a standard type, such as, the .7Crescent fuse manu-v factured bythe Ensign Bickford Co., Simsbury, Connecticut, otherwise known asMiners safety fuse, which gives time delays of 30 to 90 seconds perfoot. l This type of fuse gives more satisfactory performance if driedto reduce its moisture contents to less than about 2% and preferably toless than 1.7%, although ordinarily it has on an average 3.5% moisture.The moisture resistance of the delay fuse may be further improved byreplacing the'usual fibrous jute covering of the powder train by amaterial, such as, glass, wool, asbestos, nylon, or the like, which doesnot absorb moisture. At the initial igniting end, the fuse is in firmcontact with a quick match composition 35, such as formed of Army blackpowder, Grade A No. 6, and collodion. This composition in turn is iniirm contact with a short iength of Navy quickmatch which is readilyignited by the flame generated by the explosion in the nose cup 2 andtransmitted to the Navy quick-match by a flash hole %2" in diameter. Thedelay fuse and Navy quick-match junction is maintained by a suitablecrimp. At the other end, the delay fuse is secured in contact with adetonator 36 e. g., a tube containing lead azide, by crimping to adetonator holder sleeve 37 fixed by crimping to the bottom of the delayfuse cup 32. The lower part of the detonator 36 is surrounded by a highexplosive filling 35i, such as tetryl or TNT, contained in the end cup39. The end cup 39 is forced with a press fit snugly into an adaptedsleeve 40, which is brazed to the end of the casing l. A rubber gasket41 may be placed betweenvthe upper edge of the cup 39 and the bottom ofthe powder chamber cup 2. A strip of'metal 42 fitted into the top of thedelay fuse holder cup 32. serves to keep the coiled delay fuse 33 inplace and to position the Navy quick-match end under a vent hole in thebottom of nose cup 2.

With the added feature of a fragmentation unit, the bomb functionsefliciently to first eject its incendiary or chemical charge.

The tail ejection bomb, based on the principles set forth by thisinvention, may be modified in various respects, as for example, in theconstruction of the fuze for setting off a propellant charge, thehousing of the fuse and propellant powder charge, the design of the ightstabilizing 7 sembly'at the tail end of the bomb and the nature of thearge. The described tail ejection bomb, also, is adapted for .argingwith various other chemical agents, such as, white xosphorus, liquidvesicants, or solid agents in powdered rm. The action of the tailejection bombs in penetrating a rget has been described. In landing onearth instead of 1 unyielding structure, the bombs tend to sink into the'ou'nd to the extent of several inches, depending on the lrdness of theground, since the fuze action is not inantancous; and, in general, theytend to be tilted to some :tent from a vertical position when theydischarge their lemical contents to set up a high concentration of theected charge.

In contrast to the scatter type of chemical bombs, there a far reachingdistribution of the charge from the tail ection bomb over thesurrounding area instead of'a crasring and excessive discharge within alimited area just round the place where bomb lands. Also, in contrast to:atter type bombs hitherto known, the tail ejection type omb of thepresent invention gives the more desirable rojection of the chemicalr'illing Without the need of a omplicated fuze or high explosive bursterthat requires large amount of critical high explosive, and is moreuitable for clustering'to obtain pattern bombing.

While this invention pertains to an assembly of co- `perative componentsfor accomplishing the objects set orth, it is not concerned specificallywith any particular ype of fuze mechanism, fuze housing construction,tail asembly construction, or manner of loading with a chemical 111er.hat each of these component parts of the tail ejection )omb is subjectto modications.

The fuze construction illustrated in Figs. 1 and 6 forms ubject matterclaimed in an application by Lyle M.

It has been indicated in the foregoing description Y ooper, Serial No.562,370, led November 7, 1944, now l' ?atent 2,666,389, granted January19. 1945. The cloth sock loading of incendiary oil is subject matterclaimed n an application filed November 7, 1944, by Francis R. Russelland William T. Knox, Ir., Serial No. 562,369. tt is to be understoodthat other modifications and variaions may be carried out withoutdeparting from the spirit and scope ofthe invention as dened by theappended claim.

We claim: Y A tailejection bomb; comprising a thin-walled elongatedcasing hexagonal incrossfsection with a length Yto width as a propellantcharge adjacent the fuze in the nose cup,V

a rupturablesealing diaphragm closure for space conned surrounding thefuze and propellant powder container so that the volume of Vthis spaceis no greater than 10 times the volume of the propellant powder, athin-walled cup hexagonal in cross-section crimped at the edge of itsside walls to the tail end of the casing to be released by developmentof up to about 150 lbs. per sq. inch pres# sure inside the casing byexplosion ofV the propellant powder, an extensible flight stabilizingmeans attached to the tail cup and normally compressed therein, and achemical agent lling in the casing between said sealing diaphragm andthe tail cup.

Referencescited in the le of this patent UNITED STATES PATENTS 1,005,578Schneider Oct. 10, 1911 1,276,635 Foxworth Aug. 20, 1918 1,305,751Stearns V June 3, 1919 1,326,258 Graumann Dec. 30, 1919 1,484,190 RayFeb. 19, 1924 2,119,697 Anderson June 7, 1938 2,217,645 De Wilde etal.Oct. 8, 1940 2,247,111 Batchelor et al. June 24, 1941 FOREIGN PATENTS18,569 Great Britain of 1899 121,045 Great Britain Dec. 5, 1918 307,149Germany Feb. 6, 1920 616,917 France Nov. 6, 1926 711,463 France June 30,1931

